1. Field of the Invention
The present invention relates generally to the packaging of semiconductor devices. More particularly, the present invention relates to a reduced thickness semiconductor optical communication device package and a method of fabricating the same.
2. Description of the Related Art
In general, optical communication is a method by which information is transmitted and received by means of light.
When information is required to be transmitted, the information is first converted to an electrical signal, which is then converted again to a communication signal and then sent to a laser diode, that is, a light-emitting diode. The laser diode converts the electric communication signal to an optical signal, which is then transmitted through an optical fiber. An apparatus for converting the electric signal to the optical signal and transmitting the optical signal to the optical fiber is called a transmitter. After being outputted from the transmitter and then transmitted through the optical fiber over a long distance, an amplification circuit restores the attenuated original signal wave, which is then converted to an electric signal by a photo detector for detecting the light, that is, a light receiving element. The light receiving element, which plays the opposite role to that of the transmitter, is called a receiver.
In the light transmitter and receiver, the most important component is the optic semiconductor package, a light coupling module which converts the electric signal to the optical signal of the optical fiber and the optical signal to the electric signal. The optic semiconductor package includes optical elements, such as a laser diode and a photo detector, optical fibers, and parts for packaging the optical elements and fibers.
Two kinds of methods, active alignment and passive alignment, are generally employed in coupling the optical fiber for transmitting light with the optical elements. Presently, the optic semiconductor package employing active alignment is most utilized. In the optic semiconductor package by the active alignment, an optical element usually adheres to a substrate and the optical element and the substrate are electrically connected with each other by a conductive wire. Thereafter, a metal can, to which glass is attached, is coupled to the substrate over the optical element, and the optical fiber is adjustably fixed to the glass attached to the metal can. Thereafter, the position of the optical fiber is precisely adjusted according to the change of the electric or optical signal after the optical element is operated, and the optical fiber is completely fixed to the metal can in an optimal optical coupling state by means of laser welding, soldering, or epoxy adhesion.
In the conventional optic semiconductor package as described above, although the optical fiber and the optical element can be completely fixed in relation to each other, and, in comparison with the passive alignment method, measurements can be easily carried out, the optical fiber may be minutely tilted or the position of the optical fiber may be minutely changed in the optic semiconductor module even after the optic semiconductor module is mounted to an external device.
The tilt or the change of the position of the optical fiber means a misalignment of the optical fiber core and an optical wave-guide between the optical fiber and the optical element, which remarkably deteriorates the optical coupling efficiency. Further, in the conventional optic semiconductor package, the overall dimension of the optic semiconductor module is increased. Not only is the optical element located on the substrate on which the metal can is placed over the optical element, but also an additional long conductive pin for packaging the module to the main board has to be arranged in the module. Also, due to the large number of parts described above, the process of manufacturing the optic semiconductor module is complicated and costly.